Begin by subtracting #5# from both sides to get the #z# term by itself. This gives you:

#2z>=1470#

Then divide by #2# on both sides to get #z# by itself. This will give you:

#color(red)(z>=735)#

This can be checked by picking a value greater than #735# and a value less than #735# and testing them against the original inequality.

For example, let's try #600# and #800#.

#600# is less than #735#, so the inequality shouldn't work.

#2z+5>=1475#

#2(600)+5>=1475#

#1205>=1475# -- which is **not** true.

As for #800#, this should work because it is greater than #735#.

#2z+5>=1475#

#2(800)+5>=1475#

#1605>=1475# -- which **is** true.